1. Field of the Invention
In general, the present invention relates to systems and methods that are used to provide a warning to the drivers of large trucks that the current driving conditions and truck load conditions may cause the truck to tip over if not corrected.
2. Description of the Prior Art
Tractor trailer trucks are used to transport a countless number of products from point to point along the roads. Different products are packed in a variety of ways within the confines of a tractor trailer. For example, goods are often simply stacked within the trailer. Other times goods are hung from supports within the trailer. Still other times, goods are packed on pallets and the pallets are stacked in the tractor trailer.
As a tractor trailer drives from point to point, the cargo within the tractor trailer experiences many different forces. As a tractor trailer accelerates and decelerates, the cargo is biased backward and forward, respectively, within the trailer. As the tractor trailer drives over potholes and uneven pavement, the cargo is shaken. Similarly, as a tractor trailer moves around curves, the resulting centrifugal forces cause the cargo to be biased from side to side.
When a tractor trailer or other large truck is loaded, the cargo is placed in the trailer in a manner that distributes the weight of the cargo evenly. In this manner, the center of gravity associated with the trailer is not significantly changed. Furthermore, the weight is evenly distributed across the wheels of the trailer, which makes the suspension and the brakes of the trailer work more efficiently.
However, due to the forces that are experienced by the cargo in a trailer, it is not uncommon for cargo to shift within the confines of the tractor""s trailer. When the cargo shifts, the center of gravity associated with the tractor""s trailer also shifts. If a driver is not aware of the shifted cargo and the new center of gravity of the load, the driver may turn the tractor trailer too sharply and cause the trailer to tip over. Similarly, if the cargo shifts in the middle of a turn, the sudden change in the trailer""s center of gravity may cause the otherwise safe turn to result in the trailer tipping over.
Tractor trailers that are carrying hanging loads and tanker trucks that carry liquid loads have variable centers of gravity because such cargo loads shift constantly. Normally, the drivers of such trucks are aware of the shifting load and compensate accordingly. However, such loads often shift with more force than is anticipated and dramatically change the center of gravity for the load. If such an unanticipated shift occurs, it can cause a simple maneuver to result in the load tipping over.
Tractor trailer drivers often rely upon experience in handling driving situations where a cargo load shifts. However, experience is not always enough. If load shifts, a driver may not realize that fact until the truck is being driven into a sharp turn. At this point, it may be too late and the truck may tip over.
In the prior art, there have been different systems created to help drivers realize that the loads they are carrying are in danger of tipping over. However, such systems are typically confined to dump trucks that elevate their loads in order to dump the load. Such prior art systems are exemplified by U.S. Pat. No. 4,988,974 to Fury, entitled Warning And Safety System Indicating Truck Trailer Tip-Over Condition and U.S. Pat. No. 3,640,578 to Finney, entitled Leveling System For Semi End Dump Trucks. Such systems are used when the truck is at a full stop and a load is being dumped. Such systems cannot be used to dynamically monitor the stability of a truck load as the truck is in motion.
A need therefore exits for a system and associated method that can be adapted for use on tractor trailers and tankers that monitor the condition of the cargo load while the truck is in motion and warns of conditions that may result in a tip-over. This need is met by the present invention as is described and claimed below.
The present invention is a system and method for warning of a tip over condition in a motor vehicle, such as a tractor trailer, that is carrying a cargo load. The system can be built into the motor vehicle or added to the motor vehicle as needed. The system includes at least one left side sensor for sensing a proportion of the cargo load carried on the left side of the motor vehicle""s cargo section. Similarly, at least one right side sensor is provided for sensing a proportion of the cargo load carried on the right side of the motor vehicle""s cargo section. A microprocessor is coupled to both the left side sensors and the right side sensors. The microprocessor calculates a ratio of the cargo load borne by the left side of the motor vehicle and the right side of the motor vehicle. An alarm is provided that is coupled to the microprocessor. The microprocessor sounds an alarm when the calculated ratio or the rate of change in the calculated ratio exceeds a predetermined threshold value, thus indicating a potential tip over condition.